The present invention relates to a method of and to an apparatus for puffing (i.e., for increasing the specific volume of) tobacco, especially for puffing comminuted tobacco ribs. More particularly, the invention relates to a method of puffing particles of tobacco in an apparatus wherein the particles are caused to advance from the inlet to the outlet of a tunnel and are simultaneously contacted by steam.
Commonly owned U.S. Pat. No. 4,298,012 granted Nov. 3, 1981 to Waldemar Wochnowski discloses a method of increasing the specific volume of tobacco ribs by transporting such particles of tobacco with a vibratory conveyor and contacting the thus transported particles with steam. This entails condensation of steam on the particles of tobacco and highly satisfactory heating of the particles so that the liquid which is confined in the interior of the particles evaporates with attendant puffing of the treated material.